Why perform a bone graft?
A minimum amount of bone is essential for the placement and durability of a dental implant.
In some cases of bone insufficiency, it is necessary to reconstruct the missing bone volumes.
A pre-implant (before placement of the dental implant) or peri-implant (at the same time as the placement of the implant) bone graft must then be performed.
Different types of bone reconstruction materials:
Several types of materials and techniques are available to us for bone reconstruction.
The choice is made according to the surgical technique used, and the preferences expressed by the patients.
The bone used comes from the patient himself.
A second surgical site (mainly at the mandible) is required to remove the bone.
The surgical intervention is longer and has more postoperative pain, because it exposes 2 sites.
The bone used comes from another human.
The bone most often comes from a patient’s femur head. It is treated, which makes it lose its possibly contaminating character but also it makes it lose some of its properties.
The surgery is shorter, but the results may be inconsistent.
Bone biomaterials are substitutes, that is, they replace autogenous bone grafts.
The surgery is shorter, but the placement techniques must be adapted.
Biomaterials come from different origins:
- Xenogens, of animal origin:
The bone most often comes from cattle.
It is treated to eliminate any risk of contamination.
These materials are more than 20 years old and have been the subject of a large number of scientific publications. This currently makes them the materials of choice, because it allows shorter surgical procedures, with reproducible results.
At Neve dental clinic, we mainly use Biomaterials brand Geistlich Pharma, brand with the most scientific publications.
Bone is made chemically.
These materials have limited properties and inconsistent results, which makes their use very rare.
Growth factors are small proteins that can speed up certain processes, such as healing and bone formation, … However, they are banned from use in Europe and in many countries.
Some protocols, or biomaterials claim to contain them, but there is not sufficient scientific evidence to use them at present.
Alternatives to bone grafts?
In some cases, short or narrow dental implants can be used to avoid bone grafts.
Recent technological advances have made it possible to design implants of small dimensions with interesting mechanical properties.
However, they are not suitable for all situations of low bone volume.
The different bone reconstruction techniques:
It is sometimes necessary to carry out bone reconstruction in height and / or thickness.
There are many techniques for bone reconstruction.
The technical solutions applicable to overcome the lack of bone are different depending on the nature of the defect, its volume, but also depending on its location.
When the bone insufficiency is significant, the reconstruction procedure is mainly carried out before the placement of the implant. A waiting period of 4 to 9 months is then necessary before the implantation of the dental implant.
When the bone insufficiency is moderate, the reconstruction and the placement of the dental implant can be carried out during the same intervention.
- Alveolar bone preservation
After the tooth extraction, a reduction in bone volume appears irreparably.
This loss of volume can have consequences on the installation or the durability of the future dental implant.
There are procedures to limit this process of bone loss.
During atraumatic extraction, a biomaterial is placed in the extraction socket protected by collagen or a gum graft.
This keeps a bone volume favorable to the placement of a dental implant, and avoids, most of the time, complex grafts in a second step.
Extraction with alveolar bone preservation
- Sinus floor elevation or sinus lift
The sinus is a cavity in the maxillary bone located above the premolars and molars.
It is common that after extraction of the premolars and maxillary molars, the bone height available under the sinus is insufficient to place dental implants.
It is necessary to raise the sinus floor, the procedure is also called sinus lift, or sub sinus bone graft.
The sinus membrane is gently lifted and a biomaterial is placed under this membrane, to keep it displaced in the desired position. This results in the creation of an ossification zone, in which it is your own bone cells that reform the desired bone.
Sufficient bone volume is usually created in 4 months.
There are two methods of raising the sinus floor:
- Lateral access (Tatum technique)
Mainly for significant bone loss. Access is via the side of the bone ridge.
This technique is reliable and reproducible. Placement of dental implants cannot be done at the same time as bone reconstruction in most cases.
- Axially access (Summers technique)
Mainly for moderate bone loss. Access is via the bone ridge by the implant drilling.
This technique is less invasive, faster and generates few postoperative operations. In addition, the placement of the dental implant can be performed at the same time as the bone reconstruction.
Sinus lift by lateral access
- Guided bone regeneration
Guided bone regeneration involves creating a space for regeneration so that your own cells can recreate bone.
For this, bone biomaterials are used, whether or not mixed with autogenic bone in the form of chips, and then to maintain it in a space created by a synthetic or collagen membrane.
These techniques have been the subject of much research and improvement in recent years. There are many variations depending on the case to be treated.
These techniques are more difficult to perform, and require an experienced surgeon. But they produce very good quality bone, in large quantities and without having to use a large volume sample from another site.
In some cases, the dental implant can in some cases be placed at the same time as guided bone regeneration.
Moderate horizontal guided bone regeneration
Vertical guided bone regeneration
- Bone graft
Bone grafting involves transplanting a bone fragment.
From the patient himself with autografts or from an allogenic block, coming from another human.
The bone block is immobilized with screws at the site to be increased. After about 4 months, the added bone block binds to the jaw. The implant can then be placed in sufficient bone volume.
These techniques have been used for many years.
They produce good quality and quantity of bone with autogenous grafts, but use a sample from another site.
With allogeneic transplants, there is no second site, but the results are more inconsistent.
Autogenic apposition graft